Apparatus for maintaining a special atmosphere above a casting mold



D United States Patent 1 3,545,529

[72] Inventor Robert J. Keene [56] References Cited ig gg? lleishls Illinois UNITED STATES PATENTS PP 7 311,902 2/l885 Lewis 164/337 1 Filed March 1968 3 176 357 4 1965 N 1 249 105x 451 Patented Dec. 8, 1970 [73] Assignee United States Steel Corporation Primary Examiner-J. Spencer Overholser a corporation of Delaware Assistant ExaminerJohn E. Roethel AttorneyWalter P. Wood [54] APPARATUS FOR MAINTAINING A SPECIAL ATMOSPHERE ABOVEACASTING MOLD ABSTRACT: A frame dimensioned to fit the top of a slab 5 Claims 8 Drawing Figs mold for continuous casting is fitted with a pair of sliding clo- [52] US. Cl 164/259, sure plates which jointly engage and support a ring or collar l64/66, 249/l2l, 249/204 through which a teeming nozzle is introduced. Each plate car- [5i] Int.Cl. B22d 27/00 ries a manifold extending thereacross and connected to an [50] Field of Search 164/4, 66, inert-gas supply. Gas nozzles spaced along the manifold 152, 253, 254, 256, 257, 258, 259, 281, 335, 33l, 61,63,64, 65;249/l2l, 204, 105, 108; 141/31 1, 390, 392; l8/26(lnquired) discharge jets sweeping the surface of liquid metal in the mold. The plates have observation windows therein. Protective hoods are removably disposed over the windows.

PATENTED w: 8 I970 SHEET 1 BF 2 T1E=Lp INVENTOR APPARATUS FOR MAINTAINING A SPECIAL ATMOSPHERE ABOVE A CASTING MOLD This invention relates to continuous casting and, in particular, to means for confining a protective atmosphere in the casting mold above the surface of the liquid metal therein.

BACKGROUND on THE INVENTION BRIEF SUMMAR Y OF THE INVENTION In a preferred embodiment, I employ a frame fitting on top of the mold, having I slideways for a pair of closure plates. These plates when moved together jointly cover the mold cavity and support a ring or collar through which the'extension tube of a ladle nozzle may be inserted. Each plate carries a manifold therebelow from which extend nozzles delivering jets of inert gas sweeping the metal surface and displacing the oxygen-bearing atmosphere therefrom. A hood with a viewing window may be placedon each plate or the plates themselves may be fitted with windows. I o

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment.

BRIEF DESGRIPTION OF THE DRAWINGS DETAILED DESCRIPTION or THE PREFERRED EMBODIMENT Referring now in detail to the drawings, a tubular flowthrough water-cooled mold is adapted to receive molten metal from above and deliver from its lower end a continuous columnar casting of a section corresponding to that of the mold cavity. A frame 11 dimensioned to overlie the cavity has lugs 12 whereby it may be secured on top of the mold. The

frame has parallel ways 13 thereon slidably accommodating between them a pair of plates 14, which together substantially cover the top of the mold cavity. The plates have windows 14a and 15a therein which may be glazed with tempered glass. The adjacent edges of the plates have aligned semicircular notches together forming a seat for a split graphite ring or collar 16 in which a circumferential exterior groove 17 (FIG. 5a) is formed to accommodate the edges of the notches.

Each of the plates 14, 15 has a manifold 18 therebelow supported by pipes 19 extending vertically through the inner edge of the plate and connected to the ends of the manifold (FIG. 4). A supply yoke 20 is connected to the upper ends of pipes 19 and has a connection 21 to a source of suitable inert gas, such as argon, under pressure. Nozzles 22 spaced along manifolds 18 discharge argon jets sweeping the surface of the molten metal in mold 10.

ladle thereabove. Plates Hand 15 are partially retracted or whollyremoved when the ladle and its extension tube are being brought into position. Thereafter the plates are moved into the illustrated positions and the inert gas is supplied to pipes 21. The gas affords a protective atmosphere for the surface of the molten metal and prevents oxidation. My mold cover confines the special atmosphere but permits slight leakage when a positive pressure of inert gas above that of the outside atmosphere is maintained in the mold cavity. The jets from nozzles 22 tend to collect scum floating on the metal at the ends of the mold from which positions it may be readily spooned or dipped on removal of plates 14, 15.

Box hoods 23 may be placed on plates l4, 15 with their open ends adjacent. 'I'hehoods have glazed observation windows 24. When the hoods are employed, the glazing of the window openings in plates 14, 15 may be omitted.

It will be evident that my invention has the advantage of providng a protective atmosphere above the metal in the mold so as to prevent oxidation of the metal and the resultant formation of scum. Graphite ring permits mold 10 and plates 14 and 15 to reciprocate vertically while the nozzle-extension tube remains stationary.

Although I have disclosed herein the preferred practice of my invention, I intend to cover as well any change or modification therein which may be made without departing from the spirit and scope of the invention as set forth in the claims.

I claim:

1. The combination with a tubular casting mold having a metal receiving cavity therein of a frame overlying the mold cavity, a pair of cover plates slidable on said frame effective jointly to constitute a closure for the top of said cavity, a collar supported by said plates, a nozzle tube extending into the top of the mold and means connected to said tube for introducing gas to said mold.

2. The combination defined by claim 1 characterized by said collar being a split annulus, the halves thereof being seated in the adjacent edges of said plates.

3. The combination defined by claim 1 characterized by gas manifolds suspended below said plates, and nozzles on said manifolds, directed away from a transverse plane through the mold.

4. The combination defined by claim I characterized by spaced ways on said frame guiding movement of said plates therealong.

5. The combination defined by claim I characterized by a box hood removably positioned on each plate. 

